Electrode for barking of timber by electric current

ABSTRACT

An electrode for barking of timber by electric current, introduced into the border layers between the wood and the bark, consisting of partial electrodes linked to an endless band, adapted for penetrating into the bark, which partial electrodes remain in the course of passage of the timber through the barking device stationary in the bark for their whole operating period.

write States Pate Bumerl Aug. 28, 1973 ELECTRODE FOR BARKING 0F TIMBER [56] References Cited BY ELECTRIC CURRENT UNITED STATES PATENTS Inventor: Milan Bumerl, y 3,566,938 3/1971 Wehr.... 144/2 2 Czechoslovakia 2,707,007 4/1955 Shuff..... 144/2 Z M 8 71 X [73] Assignee: Vedecky lesnicky ustav Vysoke skoly 265596o 10/1953 3/1 zemedelske v Praze, Kostelec nad Cemymi lesy Czechoslovakia Primary Examiner-Andrew R. Juhasz Assistant Examiner-W. D. Bray [22] Filed: Jan. 20, 1972 Atmmey A1-thur 0 Klein 21 Appl. No.: 219,430

' [57 ABSTRACT [30] Foreign Application Priority Data An electrode for barking of timber by electric current, Feb. 15, 1971 Czechoslovakia 1104/71 introduced into the border layers between the wood and the bark, consisting of partial electrodes linked to 144/203 144/2 7 an endless band, adapted for penetrating into the bark, [51] Int. Cl 827i 1/00 which partial electrodes remain in the course of pas- [58] Field of Search 83/171, 651.1; sage of the timber through the barking device stationl44/208 R, 208 A, 208 C, 208 K, 208 F, 208 ary in the bark for their whole operating period.

4 Claims, 5 Drawing Figures ELECTRODE FOR BARKING OF TIMBER BY ELECTRIC CURRENT BACKGROUND OF THE INVENTION This invention relates to an arrangement of an electrode for barking of timber by electric current.

The barking of wood using electric current takes advantage of the higher humidity of the cambial and adjacent layers with respect to the external and internal layers both in just felled timber and in timber weeks and even months after cutting, depending on conditions at which the wood has been stored. As the cambial and the adjacent layers contain more humidity and in water dissolved materials than the wood and the external bark layers, their electric conductivity is higher than that of the other layers and passage of electric current causes an increase of temperature of these layers. Due to quickly generated steam and due to the influence of higher temperature and other physical and chemical influences the cohesion of the wood and the bark is reduced. The bark can be easily peeled off or it falls away itself. The separation takes always place in the border layer between the wood and the internal bark layers. By this method timber can be barked the whole year, even at vegetative rest conditions. The barking is perfect and no losses of wood are experienced.

The applied electrodes are knives which penetrate through the bark to the cambial layer. These knives can be arranged either in concentric circles or in direction of the wood fibers. The voltage of the supplied electric current depends on the humidity of the wood, on the length of the knife, on the temperature of the layers, on the distance of both electrodes and on the direction, in which the knives penetrate into the bark, whether parallel or perpendicularly to the wood fibers.

The expression bark should cover all layers of tissue beyond the cambial layer. It is necessary to provide for this method of barking a perfect and well conductive connection between the electrodes and the layers below the bark, particular the cambial layer. In the course of a steady movement of the short or long wood in its longitudinal direction a steady and perfect contact of the electrodes with the layers below the bark must be maintained.

SUMMARY OF THE INVENTION It is an object of this invention to provide an improved electrode for barking of wood, which would safeguard a perfect electric connection of the electrodes with the layers below the bark in the course of the whole action of the electric current.

It is another object to provide an electrode, which would easily penetrate the bark and would stick therein without relative motion with respect to the barked wood within the whole time interval within which electric current is applied to the respective place.

It is still another object of this invention to provide an electrode for barking of wood, which could be easily handled with the least required attention of the attendant.

Bearing these and other objects in mind, an electrode for barking of wood is proposed, composed of a number of partial electrodes, adapted for penetrating through the bark and linked together to form an endless band. This endless band of partial electrodes is advantageously guided within a gap between lateral guiding ledges and is supported by a guiding roller and by a tension roller with a tenioning device. The guiding roller, the tension roller and the guiding ledges are advantageously connected to a pressure and feeding device by means of a resilient pressure transmitting device. A contact pressure devices is furthermore provided in the active part of the guiding ledge between the guiding and tension roller.

An advantage of this arrangement is a higher efficiency of the barking device enabling a perfect electric contact of the electrodes with the damp tissues below the bark even in the course of the continuous uninterrupted passage of the barked wood through this barking device.

DESCRIPTION OF DRAWINGS An exemplary embodiment of an electrode for barking of wood by means of electric current is shown in the attached drawings, where FIG. I is an overall elevation of the electrode,

FIG. 2 a side view in the direction of the arrow indicated in FIG. 1 by S;

FIG. 3a a detailed side view showing the interconnection of individual partial electrodes to an endless band, FIG. 3b a plan view of the same details and FIG. 4 a schematic view of the major parts of a barking device in the direction of the axis of the barked wood.

DESCRIPTION OF PREFERRED EMBODIMENT The electrodes according to this invention are supported by a supporting frame 1, (see FIG. 4) and comprise a device 2 for generating pressure and a feeding movement, an electrically insulating insert 3, an encasing 4, guiding ledges 5, a guiding roller 6, a tension roller 7, a tensioning element 8, a resilient pressure transmitting element 9, a contact pressure element 10 and an endless band 11 comprising partial electrodes 12.

The partial electrodes 12 are mutually linked to an endless band 11, guided in a gap between guiding ledges 5, and passing over the guiding roller 6 and the tension roller 7.

The partial electrodes 12 are by means of the pressure and feeding device 2 subsequently pressed into the bark in the course of passage of the timer 15 through the whole arrangement. The partial electrodes 12 are maintained in their position after they have penetrated through the bark without any relative movement with respect to the wood in the course of passage of the wood through the whole active part of the device between the guiding and tension rollers by means of the contact pressure device 10. The contact pressure device 10, supported on the active part of the guiding ledges 5 enables together with the resilient pressure transmitting device 9, which transmits pressure to the guiding ledge 5, to the guiding roller 6 and to the tension roller 7, to establish and maintain a perfect contact of the partial electrodes 12 with the cambial layer even if there are irregularities of the surface of the treated wood, particularly deviations from a circular cross section and changes of the diameter of the barked wood.

The endless band 11 composed of partial electrodes 12, guided in a gap between guiding ledges 5 and over the guiding roller 6 and tension roller 7, is brought to movement after the partial electrodes 12 have penetrated the bark of the barked timber by the forward movement of the timber caused by means, not shown on the drawings. The endless band 11 with the partial electrodes 12 passes thereby over the guiding roller 6 and tension roller 7, whereby the partial electrodes 12 remain within the whole period of passage of the barked timber through the barking device at their place in the bark, taken along by the timber, which they leave only when passing over the tension roller 7.

The endless band 11 is composed, as shown in FIG. 3 of partial electrodes 12 linked by straps 13 by means of rivets 14. The length of the partial electrodes 12 can be adjusted to conditions and optimum dimensions depend on the forward speed of the barked timber, on the voltage of the used electric current and on conditions of the timber. The partial electrodes can have the shape of short knives with cutting edges, of needles, of cutting disks and similar. The interconnection of the partial electrodes 12 to an endless band 11 can be accomplished by means of connecting straps, bolts, rivets, V belts and similar. Individual parts of the partial electrodes 12 can be made of metal, plastics and other materials.

FIG. 4 shows a barking device in a view in direction of the axis of the barked timber 15. The individual electrodes are arranged on the frame 1 in concentric circles and are pressed by devices 2 generating pressure and a feeding movement towards the timber 15, which rests on supporting rollers 16 and is advanced by a not shown device in its axial direction through the barking device. As the diameter of the timber is variable and as for certain operating conditions, that is for a certain humidity and kind of the timber and a certain voltage between adjacent electrodes, acertain distance between adjacent electrodes is most advantageous for efficient working, the electrodes are arranged on the frame l as electrode heads in several concentric circles so that they can be brought into operation subsequently in case the diameter of the timber increases, in order that the distance between adjacent electrodes always remain within a predetermined range. For Norway spruce timber having a humidity of about 50 percent, an A.C. voltage 220 V at 50 cycles, the distance between adjacent electrodes should be between 1 and 3 cm, whereby the time interval of action of the electrodes is between 12 and seconds. At higher voltages this time interval can be reduced to several seconds, higher voltages are of course generally not recommended for safety reason. When additional electrodes are introduced, it is of course necessary to switch over the individual sets of partial electrodes in order to have opposite polarities of adjacent electrode sets. The individual electrodes are advantageously arranged adjustable on the supporting frame 1 in order to enable to adjust the electrodes to the correct distance from the worked timber.

It is obvious that the described arrangement is solely one of different possible embodiments of the object of this invention which is not limited to this construction.

I claim:

1. Electrode for barking of timber by electric current introduced into the border layers between the wood and the bark, said electrode composed of a number of partial electrodes with sharp parts for penetrating through the bark, said partial electrodes linked together to form an endless band having an upper strand and a lower strand, said sharp parts forming the external circumference of the endless band, means for free guiding said endless band and means for pressing one strand of said endless band facing the timber to be barked towards the advancing timber.

2. Electrode as set forth in claim 1, said means for free guiding said endless band comprising lateral guiding ledges, a guiding roller and a tension roller with tensioning means.

3. Electrode as set forth in claim 1, said means for pressing one strand of the endless band facing the timbet to be barked against the advancing timber comprising an adjustable pressure and feeding device and resilient pressure transmitting means.

4. Electrode as set forth in claim 2 comprising in addition a contact pressure device maintaining pressure of the strand of the endless band facing the timber to be barked between its guiding and pressure roller. 

1. Electrode for barking of timber by electric current introduced into the border layers between the wood and the bark, said electrode composed of a number of partial electrodes with sharp parts for penetrating through the bark, said partial electrodes linked together to form an endless band having an upper strand and a lower strand, said sharp parts forming the external circumference of the endless band, means for free guiding said endless band and means for pressing one strand of said endless band facing the timber to be barked towards the advancing timber.
 2. Electrode as set forth in claim 1, said means for free guiding said endless band comprising lateral guiding ledges, a guiding roller and a tension roller with tensioning means.
 3. Electrode as set forth in claim 1, said means for pressing one strand of the endless band facing the timber to be barked against the advancing timber comprising an adjustable pressure and feeding device and resilient pressure transmitting means.
 4. Electrode as set forth in claim 2 comprising in addition a contact pressure device maintaining pressure of the strand of the endless band facing the timber to be barked between its guiding and pressure roller. 